Guillaume is a distinctive boys' name in United States, ranking #3648 in 1997 with 19 recorded births. The name reached its all-time peak in 1997 with 19 births ranking #3648. Since 1996, the popularity has increased by 18.8%. In 1997, approximately 1 in every 99,215 boys born was named Guillaume. FALLING Recent data shows the name is currently falling.